Wrist-pin.



W. AAB.

WRIST PIN.

APPLICATION FILED MAR. I3, |919.

Lzl Patent-ed Nov. 25, 1919.

WILLIAM AAB, QF NEW ULM, MINNESOTA.

WRIS

rApplication filed March 13, 1919.

1/ l) all cli/0m it may concern:

Be it known that l, l/VILLIAM AAB, a citizen of the United States,residing at New Ulm, in the countyof Brown and State of Minnesota, haveinvented certain new and useful improvements in VVrist-Pinsg and l dohereby declare the following to be a full, clear. and exact descriptionof the invention, such las will enable others skilled in the art towhich it appertains to make and use the same.

Mfy invention relates to improvements in wrist pins intended for generaluse, but especially adapted for use in attaching connecting rods to thepistons of internal com bastion engines. 1

To the above end, generally stated, the invention consists of the noveldevices and combination of devices hereinafter described and defined inthe claims.

in the accompanying drawings, which illustrate the invention, likecharacters indicate like parts throughout the several views.

Referring to the drawings: l

Figure 1 is a view in central section illustrating` the piston of aninternal combustion engine attached to its connecting rod by theimproved wrist pin;

Fig. 2 is a perspective view of the i1nproved wrist pin;

Figs. 3 and i are fragmentary views principally in central sectionillustrating one method of securing the expanding key in the wrist pin;and

Fig. 5 is a view principally in central section illustrating the use oftwo expanding keys.

The numeral 6 indicates the piston of an internal combustion engine andthe numeral 7 indicates the connecting rod thereof. A pair ofdiametrically opposite radial wrist pin holes or bores 8 is formed inthe sides of the piston 6 and in inwardly projecting bosses 9 integrallyformed therewith. The end of the connecting rod 7 in the piston 6 isprovided with a cap bearing 10 alined with the bores 8 to receive awrist pin and the cap thereof is adjustably secured to said connectingrod by nut equipped bolts 11. The parts thus far described are of wellknown standard construction.

The improved wrist pin, indicated by the numeral l2, is mounted in thebosses 9 and cap bearing 10 and'connects the piston 6 to Specificationof Letters Patent.

-PIN.

VPatented'lrov., 25, 1919.

Serial No. 282,376.

its connecting' rod 7. A relatively large eccentric bore 13 extendscompletely through the wrist pin 12, and a tapered key seat le, the axisof which is parallel to the axis of said bore, is also extendedcompletely through` the thick portion of the wrist pin.

vrlhe wrist pin 12 is radially slit, at l5, through its thick portionand from end to endlthereof. lt will also be noted, as best shown inFig. 2, that the slit extends axially through the key seat 14 from thebore 13 to the outer face `of the wrist pin, thus leaving only arelatively thin portion of metal at one side of the wrist pin, to=l witthe side diametrically opposite said slit. By thus forming the wrist pin12, the same may Je circumferentially expanded, as will presentlyappear, and when released will return, under a spring action, to normalposition.

'To circumferentially expand the wrist pin 12, a key 16 is provided,having the same taper as the key seat 14, and the key is driven intosaid seat 141, until the wrist pin is expanded to the desiredcircumference. Both ends of the key 16 are then cut off flush with theends of the wrist pin 12. Various means may be providedvfor holding thekey 16 in its proper place in the key seat 14, and in Figs. 1, 2, and 3,the key 16 is shown as secured in position by countersinking the smallend of the seat 14 at 17, and then upsetting the small end of said keytherein.

As shown in F ig. 1, the wrist pin 12 is expanded by the key 16 so thatit will just float or turn in the holes 8 in the piston 6 and the capbearing 10 is frictionally adjusted thereon, so that the wrist pin willturn with the connecting rod 7. 1n case the wrist pin 12, or the holeswithin which it is journaled should wear, the key 16 may be drivenfarther into the seat 11i to again expand said pin suliiciently to causethe same to snugly it the holes or bearings in which it is mounted. Theprojecting small end of the key 16 may then be cut off and the key againupset to hold the saine in position. ln place of connecting the wristpin for movement with the connecting rod 7, the saine may be expandedsufiiciently to frictionally lock said pin in the holes 8 and looselysecure the connecting rod 7 thereto, so that it will turn with respectto the wrist pin.

Referring now to the construction shown in Fig. 5, it will be noted thatthe key seat 18 is tapered from both ends of the Wrist pin 12 to thelongitudinal center thereof. A pair of correspondingly tapered keys 19are driven into the key seat -18 and their outer ends cut off iiush Withthe ends over said pin. The keys 19 are held in position by a pair ofrivets 20. These rivets Q0 are insertedV through alined bores in theWristpin k12 and keys 19. Preferably the bores are formed in the Wristpin 12 at the time thesa-me is made and the bores in the keys 19 aremade after said keys have been driven into the seats 18. .As the key orkeys extend substantially the full length of the vWrist pin, said Wristpin is not yweakened by 4the formation of the key seats therein. It

is also eminent that the key or keys evenly expand the Wrist pinthroughout its full length.

My improved Wrist pin has substantially the same Weight as an ordinaryWrist pin is liable to ruin a piston to Which it is applied.

What I claim is: 1. A Wrist pin for connecting rods, hav- Iing aneccentric bore and being slit through its thick portion, andan expandingkey Working With a Wedge action in said slit.

2. A Wrist pin for connecting` rods, having an eccentric bore and beingslit through its thick portion, yand an expanding key Working With aWedge action in saidslit,

said expanding keyy extending substantially the full length of the Wristpin.

3. A Wrist pin 'for connecting rods, having an eccentric bore and beingslit through its thick portion, a tapered key seat extending throughsaid slit longitudinally of the Wrist pin,Y and a tapered expanding keymounted in said seat.

4c. A Wrist pin for connecting rods hav- Y ing an eccentric bore andbeing slit through its thick portion, a tapered key sea-ty extendingthrough said slit longitudinallyof the Wrist pin, and a taperedexpanding key mounted in said seat and secured therein against endWisedisplacement. .Y

In testimony Whereof l aiixl my signature in presence of tWo Witnesses.`

' n WILLIAM AAB.

Witnesses:

GEORGE DEUcxsoN, A. C. AMANN.

